Superconducting current-limiting liquid nitrogen switch combined electrical appliance and its working method

Abstract

The invention discloses a superconducting current limiting liquid nitrogen switch combined electric appliance and a working method thereof. The combined electric appliance comprises a vacuum heat insulation Dewar cabinet body, a superconducting current limiting unit, a liquid nitrogen breaking unit and a liquid nitrogen circulation cooling system, wherein the vacuum heat insulation Dewar cabinet body is filled with liquid nitrogen, the superconducting current limiting unit and the liquid nitrogen breaking unit are co-located inside the Dewar cabinet body, and the two units are isolated by a vacuum heat insulation layer and electrically connected; the superconducting current limiting unit includes a superconducting tape bracket and a superconducting tape; the liquid nitrogen circulation cooling system includes a liquid nitrogen pump, a heat exchanger, a liquid nitrogen storage tank and a refrigerator; and the liquid nitrogen breaking unit includes static and moving contacts, an operating mechanism, a pressure release nozzle, a liquid nitrogen storage tank, a liquid nitrogen pump, a nitrogen storage tank and a pressurizing pump. The combined electric appliance reduces the fault current by using quench characteristics of the superconducting current limiting unit when the circuit fails, and breaks the fault current by using good insulation characteristics and good current breakingcharacteristics of liquid nitrogen; and the combined electric appliance realizes the integration of current limiting and breaking, shares the refrigeration system, saves the cost and reduces the volume of the equipment.

Description

technical field [0001] The invention relates to the field of superconducting applications and the field of switch technology, in particular to a superconducting current-limiting liquid nitrogen switch combined electrical appliance and a working method thereof. Background technique [0002] With the continuous growth of people's demand for electricity and the continuous improvement of power supply quality requirements, the scale of distribution network is expanding day by day, and the degree of grid interconnection is getting higher and higher. On the one hand, the degree of interconnection of the power grid improves the reliability of power supply and reduces the cost of power supply. On the other hand, it also reduces the short-circuit impedance of the power grid system, causing the level of short-circuit current to increase sharply, even beyond the range that the circuit breaker can handle. The current-limiting power equipment that controls the short-circuit current of the...

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Problems solved by technology

[0005] The existing similar patents are: a closed switchgear with liquid nitrogen cooling cycle system application number: 201510164304.6, the difference from this application is that the vacuum interrupter is soaked in liquid nitrogen in this patent, and the traditional vacuum circuit breaker is used to open Break the arc, while liquid nitrogen is only used as an insulating medium to avoid SF 6 It liquefies in the alpine region and loses its insulating ability

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